2-bromo- and 2-nitroxy derivatives of 3-bromo- and 3,3-dibromo-4-oxo-azetidines, and preparation

ABSTRACT

The azetidines of the present invention have the formula I ##STR1## wherein R 1  is hydrogen or bromine, 
     R 2  is hydrogen or bromine, wherein at least one of R 1  or R 2  is bromine, 
     R 3  is hydrogen; Me 2  --C═C--COOR 4  wherein R 4  is hydrogen, methyl, benzyl or some other carboxy-protective group, and 
     X is bromine or nitroxy group (--ONO 2 ). 
     According to the invention 2-bromo- and 2-nitroxy derivatives of 3-bromo- and 3-dibromo-4-oxo-azetidines are prepared by reacting derivatives of protected penicillanic acid 1,1-dioxides with DBN reactant (1,5-diazabicyclo/3.4.0/non-5-ene) and then the obtained DBN salt of sulfinic acid or isolated sulfinic acid is treated with thionyl chloride and, after eliminating thionyl chloride by evaporation, the obtained residue is passed through a silica gel column with methylene chloride or some other solvent as eluant or the obtained residue is dissolved in tetrahydrofuran or some other suitable solvent and treated with tetrabutyl ammonium bromide and after the treatment a derivative of 2-bromo, 3-bromo or 2-bromo-3,3-dibromo-4-oxo-azetidine is isolated, which derivative may be subjected to a reaction with silver nitrate in 2-propanol and, after the treatment of the reaction mixture, derivatives of 2-nitroxy-, 3-bromo- or 2-nitroxy-3,3-dibromo-4-oxo-azetidine are isolated. 
     The obtained substances are useful intermediates in the syntheses of beta lactam analogons or as components in formulations having antibacterial, inhibitory, antitumour or antagonistic action.

The invention relates to 2-bromo- and 2-nitroxy derivatives of 3-bromo-and 3,3-dibromo-4-oxo-azetidines, to processes for the preparationthereof and to the use thereof.

There are known certain 2-chloro derivatives of3-phthalimido-alpha-(1-methyl-ethylidene)-4-oxo-1-azetidine acetic acid,which are prepared by reacting methyl-6-phthalimido penicillanate withchlorine or sulfuryl chloride (Kukolja S., J. Am. Chem. Soc. 93,(1971),6267).

Haloazetidinones are also prepared by reacting penicillin withhalogenating agents such as molecular chlorine or N-halosuccinimide(U.S. Pat No. 4,159,984). Further, there is disclosed the rearrangementof oxoazetidine sulfinic acids obtained from penicillin sulfoxide, withhalogenating agents into haloazetidinones (Spitzer W. A., Kukolja S.,Goodson T., Lammert J. P., Steven R., Lilly Eli Co., EP 60 120,equivalent U.S. Pat. No. 4,368,156; Spitzer W. A., Goodson T., LammertS. R. and Kukolja S. J., Org. Chem. 46,(1981) 3569). Narisada et al.disclosed the synthesis of chloroazetidinone from methylthioazetidinonesobtained from penicillin (U.S. Pat. No. 4,138,486).

S. Kukolja and S. R. Lammert further disclosed the preparation of theabove-mentioned 2-chloro derivatives starting from trichloroethyl esterof 6-phenyl-acetamido-penicillanate (Croat. Chem. Acta 44, (1972)299-301). The Eli Lilly Company claimed the preparation ofhaloazetidinones starting from 3-exomethylene cephalosporin sulfone withthe acylamide group in the 7-position and reacting the same withactivated zinc or magnesium and ammonium chloride to obtain sulfinicacids, which acids with halogenating agents give sulfinyl chlorides,which are then subjected to hydrolysis (EP 132395).

3-bromo- and 3,3-dibromo-2-chloroazetidinones are also prepared by thereaction of pivaloyloxymethyl 6-bromo- or 6,6-dibromopenicillanate withchlorine or tertiary butyl hypochlorite (C. Somoza and O. A. Oreste,Tetrahedron 44, (1988) 7007-12.).

According to our knowledge 2-bromo- and 2-nitroxy derivatives of3-bromo- and 3,3-dibromo-4-oxo-azetidines are not known.

The object of the present invention are 2-bromo- and 2-nitroxyderivatives of 3-bromo- and 3,3-dibromo-4-oxo-azetidines of the generalformula I ##STR2## wherein R¹ is hydrogen or bromine,

R² is hydrogen or bromine,

R³ is hydrogen; Me₂ --C═C═COOR⁴, wherein R⁴ is hydrogen, methyl, benzylor some other carboxy-protective group, and

X is bromine or nitroxy group (--ONO₂).

A further object of the present invention is a process for preparing2-bromo- and 2-nitroxy derivatives of 3-bromo- and3,3-dibromo-4-oxo-azetidines of the general formula I, wherein theradicals have the above meaning, starting from derivatives ofpenicillanic acid 1,1-dioxides of the general formula II ##STR3##wherein radicals R¹ and R² have the above meaning and R⁴ is methyl orbenzyl or some other protective group, by reacting with DBN(1,5-diazabicyclo/3.4.0/non-5-ene) and then the obtained DBN salt ofsulfinic acid or isolated sulfinic acid is treated with tionyl chlorideand, after eliminating thionyl chloride by evaporation, the obtainedresidue is passed through a silica gel column with methylene chloride aseluant or the obtained residue is dissolved in tetrahydrofuran andtreated with tetrabutyl ammonium bromide and after the treatment aderivative of the general formula I wherein

R¹ is hydrogen or bromine,

R² is hydrogen or bromine,

R³ is hydrogen; Me₂ --C═C═COOR⁴, wherein R⁴ is hydrogen, methyl, benzylor some other carboxy-protective group, and

X is bromine, is isolated.

The obtained 2-bromo derivatives of the general formula I wherein R⁴ ise.g. benzyl, are converted, by eliminating the benzyl group withaluminum trichloride, into a product I wherein R⁴ is hydrogen, or aresubjected to the reaction with silver nitrate in isopropanol to obtainthe derivative of the general formula I wherein X is nitroxy group andR⁴ is benzyl.

The derivatives of 6,6-dibromopenicillanic acid are prepared from6-amino-penicillanic acid according to known processes (R. A. Volkmann,R. D. Carrol, R. B. Drolet, M. L. Elliott and B. S. Moore, J. Org. Chem.47 (1982) 3344-5; Wayne E. Barth, U.S. Pat. No. 4,234,579).

A further object of the present invention is the use of these compoundsas useful intermediates in preparing various beta lactam analogons suchas 1-oxapenems (Masyuki Murakami, Tsutomu Auki, Munenuri Matasura andWataru Nagata, J. Antibiot. 43 (1990) 1441-49; H. R. Pfaendler, T.Neumann and R. Bartsch, Synthesis (1992) 1179) or penems (V. M.Girijavallabhan, A. K. Ganguly, S. W. McCombie, P. Pinto, R. Rizvi,Tetrahedron Lett. 22, (1981) 3485-88; C. M. D. Beels, M. S. Abu Rabie,J. Chem. Soc. Chem. Commun. 1979, 665) or 1-oxacephalosporins (U.S. Pat.No. 4,013,653, U.S. Pat. No. 4,234,724, U.S. Pat. No. 4,159,984) or thepresent invention offers great possibilities for transformations intoother monobactams or cyclic compounds. Additionally, the corresponding2-nitroxy derivatives of azetidinones are also potential Ca⁺⁺antagonists such as are also nitroglycerin, nicorandil or nipradiol.

A further object of the present invention is the use of these compoundsas raw materials in formulations having antibacterial, inhibitory,antitumour and antagonistic action.

Some of the compounds of the general formula I in concentrations ofabout 10⁻⁵ M inhibit the growth of tumour cells of human cervix uteri(HeLa) by as much as 70% whereas they do not exhibit any action onnormal fibroblasts (WI38).

The presently disclosed knowledge about antitumour action of these aswell as some other analogues (e.g.3,3-dibromo-2-chloro-alpha-(1-methylethylidene)-4-oxo-azetidine-1-aceticacid) represents novel knowledge about biological activity of betalactams.

The invention is illustrated by the following Examples which are in noway limitative as to the scope thereof.

EXAMPLE 1 2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidineAcetic Acid Benzyl Ester

6,6-dibromopenicillanic acid sulfone benzyl ester (4.8 g; 0.01 mole) wasdissolved in methylene chloride (50 ml) and 1.5-diaza-bicyclo4.3.0!non-5-ene (2.08 g; 2 ml; 0.0167 mole) was added. The reactionmixture was stirred for half an hour at room temperature, then cooled to0° to 5° C., thionyl chloride (24.5 g; 15 ml; 0.205 mole) was added dropby drop, it was stirred for half an hour at this temperature and foranother hour at room temperature. The reaction mixture was evaporated toa dry residue, benzene (15 ml) was added and it was again evaporated toa dry residue. The obtained product was passed through a silica gelcolumn with methylene chloride followed by the isolation of thesubstance (1.08 g; 21.8%).

m.p. 68°-70° C.

Rf 0.72 (methylene chloride);

IR (KBr): b 1795(vs), 1730(s), 1635(m), 1395(m), 1375(m), 1270(m),1225(vs), 1125-1070(m), 815(m), 700(m) cm⁻¹.

¹ HNMR (CDCl₃)δ:2.00 (3H, s, Me), 2.34 (3H, s, Me), 5.16 and 5.25 (each1H d, J=12 Hz, CH₂ Ph), 6.30 (1H, s, C₂ --H), 7.36 (5H, s, Ar) ppm.

¹³ C(CDCl₃)APT: 22.352 and 23.875 (2 Me), 55.675 (C₃ --Br₂), 67.441 (CH₂Ph), 74.084 (C₂ --H), 117.031 (N--C═), 128.784 (Ph), 135.112 (C--Ph),158.071 (COO), 159.948 (═C(Me)₂), 162.283 (C═O).

Analysis for C₁₅ H₁₄ Br₃ NO₃ : calc.: C 36.32; H 2.84; N 2.82% found: C36.61; H 2.75; N 2.76%

Mol. mass: 496.018; m/e 477 (--H₂ O), 416 (--Br), 404(--CH₂ Ph).

EXAMPLE 2 2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidineAcetic Acid Benzyl Ester

6,6-dibromopenicillanic acid sulfone benzyl ester (3.84 g; 0.008 mole)was dissolved in methylene chloride (40 ml) and 1.5-diaza-bicyclo4.3.0!non-5-ene (1.66 g; 1.6 ml; 0.013 mole) was added. The reactionmixture was stirred for half an hour at room temperature. The obtainedsolution was treated with 0.1N hydrochloric acid and NaCl, the layerswere separated, the aqueous one was extracted two more times withmethylene chloride, dried and evaporated to dryness. To the evaporatedresidue a solution of thionyl chloride (12 ml) in methylene chloride (40ml) was added, it was stirred for half an hour at room temperature,evaporated to a dry residue, benzene (2×30 ml) was added and it wasagain evaporated to dryness. The obtained residue was dissolved intetrahydrofuran (120 ml), tetrabutylammonium bromide (2.576 g; 0.008mole) was added and it was stirred at room temperature up to thedisappearance of the starting substance (TLC). The solution was thenevaporated to dryness and was passed through a silica gel column withmethylene chloride as eluant. Combined fractions with Rf 0.72 (methylenechloride) were evaporated and treated with n-hexane to give a productwith m.p. 71°-72° C. (1.48 g; 37.75%). The remaining spectroscopic datawere identical as in Example 1.

EXAMPLE 3 2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidineAcetic Acid Methyl Ester

6,6-dibromopenicillanic acid sulfone methyl ester (0.810 g; 0.002 mole)was dissolved in methylene chloride (10 ml) and 1.5-diaza-bicyclo4.3.0!non-5-ene (0.4 g; 0.4 ml; 0.0033 mole) was added. The reactionmixture was stirred for half an hour at room temperature, then cooled to0° to 5° C., thionyl chloride (4.9 g; 3 ml; 0.040 mole) was added dropby drop, it was stirred for half an hour at this temperature and foranother hour at room temperature. The reaction mixture was evaporated toa dry residue, benzene (15 ml) was added and it was again evaporated toa dry residue. The obtained product was passed through a silica gelcolumn with methylene chloride followed by isolation of the substance(0.198 g; 23.6%).

m.p. 68°-70° C.

Rf 0.56 (methylene chloride)

IR(film): 1805(vs), 1735(vs), 1640(m), 1440(m), 1385(vs), 1370(vs),1270(s) 1230(vs), 1125-1070(bs), 815 (s) cm³¹ 1.

¹ HNMR (CDCl₃)(300 MHz)δ: 2.01 (3H, s, Me), 2.33 (3H, s, Me), 3.01 (s,3H, OCH₃) 6.42 (s, 1H, C₂ --H) ppm.

¹³ C(CDCl₃)APT: 22.286 and 23.815 (2 Me), 52.270 (OCH₃), 55.761 (C₃--Br₂), 74.020 (C₂ --H), 116.985 (N--C═), 159.275 (COO), 159.561(═C(Me)₂), 162.865 (C═O).

Brutto formula C₉ H₁₀ Br₃ NO₃

Mol. mass: 419.926; M⁺ 420, m/e 389 (--OCH₃), 340 (--Br).

EXAMPLE 43,3-dibromo-2-chloro-alpha-(1-methylethylidene)-4-oxo-1-azetidine AceticAcid Benzyl Ester

6,6-dibromopenicillanic acid sulfoxide benzyl ester (6.96 g; 0.015 mole)was dissolved in toluene (750 ml), N-chlorosuccinimide (4.02 g; 0.030mole) was added and it was heated in a nitrogen current at the boilingtemperature for 1.5 hours. After the reaction was completed,hydrochloric acid (1N, 450 ml) was added and the solution was refluxedunder refluxing condenser for one hour. The layers were separated, thetoluene layer was washed with water, dried (CaCl₂) and evaporated todryness (5.76 g; 85.2% of the crude product). The obtained product wasdissolved in methylene chloride (50 ml), triethylamine (1.5 g; 2.1 ml)was added to the solution and it was stirred at room temperature for 10minutes. Water was added to the reaction mixture, the pH was adjusted to5 to 6, the organic layer was washed with water, dried (Na₂ SO₄) andevaporated to dryness. The obtained product was passed through a silicagel column with methylene chloride as eluant, followed by isolating theproduct (1.98 g; 30%) by means of n-hexane.

m.p. 64°-66° C.

Rf 0.70 (methylene chloride)

IR(KBr)ν: 1795(vs), 1730(s), 1635(m), 1395(m), 1375(m), 1270(vs),1220(s), 1125-1070(b,m), 820(m), 700(m) cm⁻¹.

¹ HNMR(CDCl₃)(300 MHz)δ: 2.00 and 2.35 (2s, 6H, 2Me), 5.16 and 5.25(each 1H, d, J=12 Hz, CH₂ Ph), 6.06 (s, 1H, C₂ --H), 7.37 (s, 5H, Ar)ppm.

¹³ C(CDCl₃)APT: 22.281 and 23.808 (2 Me), 56.555 (C₃ --Br₂), 67.433 (CH₂--Ph), 81.305 (C₂ --H), 116.748 (N--C═), 128.941 (Ph), 135.130 (C--Ph),158.509 (COO), 160.273 (═C(Me)₂).

Mol. mass: 451.558; m/e 433 (--H₂ O); 416 (--Cl); 360 (--CH₂ Ph).

EXAMPLE 53,3-dibromo-alpha-(1-methylethylidene)-2-nitroxy-4-oxo-1-azetidineAcetic Acid Benzl Ester

2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidine acetic acidbenzyl ester (0.744 g; 0.0015 ml) was dissolved in 2-propanol (20 ml),silver nitrate (1.01 g; 0.0060 mole) was added thereto and it was heatedin a nitrogen current at the boiling temperature for 1 hour. Then thereaction mixture was filtered and the filtrate was evaporated todryness. Methylene chloride was added to the evaporated residue, theprecipitate was sucked off and the filtrate was evaporated to dryness(0.466 g; 65%). The obtained product was passed through a silica gelcolumn with methylene chloride, followed by the isolation of a substancewhich crystallized upon standing (0.418 g; 58.13%).

m.p. 69√-71° C.

Rf=0.75 (methylene chloride)

IR(KBr): 1805(vs), 1730(vs), 1660(vs), 1390(m), 1375(m), 1285(vs),1225(vs), 1140(s), 1080(m), 830(s), 760 (m), 700(m) cm⁻¹.

¹ HNMR(CDCl₃)(300 MHz)δ: 1.99 (3H, s, Me), 2,32 (3H, s, Me), 5.16 and5.27 (each 1H d, J=12 Hz, CH₂ Ph), 6.42 (1H, s, C₂ --H), 7.37 (5H, s,Ar) ppm.

¹³ C(CDCl₃)APT: 21.973 and 23.700 (2 Me), 52.935 (C₃ --Br₂), 67.344 (CH₂--Ph), 90.895 (C₂ --H), 116.654 (N--C═), 128.613 (Ph), 134.660 (C--Ph),158.290 (COO), 159.634 (═C(Me)₂), 161.669 (C═O).

Mol. mass: 478.11; m/e 432 (--NO₂); 398 (--Br); 352 (--NO₂).

EXAMPLE 63,3-dibromo-alpha-(1-methylethylidene)-2-nitroxy-4-oxo-1-azetidineAcetic Acid benzyl ester

3,3-dibromo-alpha-(1-methylethylidene)-2-nitroxy-4-oxo-1-azetidineacetic acid benzyl ester could be obtained in an analogous way as inExample 5 with the difference that the starting substance was3,3-dibromo-alpha-(1-methylethylidene)-2-chloro-4-oxo-1-azetidine aceticacid benzyl ester.

EXAMPLE 7 2,3,3-tribromo-alpha-1(1-methylethylidene)-4-oxo-1-azetidineacetic acid

Into an ice-cooled suspension of aluminum trichloride (0.400 g; 0.003mole) in methylene chloride (15 ml) in a nitrogen current a solution of2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidine acetic acidbenzyl ester (0.496 g; 0.001 mole) and anisole (0.648 g, 0.65 ml, 0.006mole) in methylene chloride (15 ml) was added drop by drop for an hourand then it was stirred at room temperature for three more hours. To thereaction mixture ethyl acetate (15 ml) and 0.1N hydrochloric acid (5 ml)were added and the layers were separated. The ethyl acetate layer wasextracted with 5% sodium hydrogen carbonate solution (2×20 ml) and thelayers were separated. The aqueous layer was acidified with 0.1Nhydrochloric acid to pH 1, then fresh ethyl acetate (20 ml) and sodiumchloride were added and the layers were again separated. The ethylacetate layer was washed with saturated salt solution, dried andevaporated to a dry residue which crystallized upon drying at 0.1 mm Hg(0.219 g; 54.0%).

m.p. 124°-6° C.

Rf=0.50 (ethyl acetate-methanol 3:1)

IR(KBr): 1800(vs), 1700(s), 1630(m), 1430(m), 1370(m), 1285(m), 1245(m)cm⁻¹.

¹ HNMR (DMSO-d₆)(90 MHz)δ: 1.89 (3H, s, Me), 2.25 (3H, s, Me) and 6.73(1H, s, C₂ --H) ppm.

EXAMPLE 83,3-dibromo-2-chloro-alpha-(1-methylethylidene)-4-oxo-1-azetidine AceticAcid

Into an ice-cooled suspension of aluminum trichloride (1.6 g; 0.012mole) in methylene chloride (55 ml) in a nitrogen current a solution of3,3-dibromo-2-chloro-alpha-(1-methylethylidene)-4-oxo-1-azetidine aceticacid benzyl ester (1.5 g; 0.003 mole) and anisole (2.79 g, 2.7 ml, 0.024mole) in methylene chloride (55 ml) was added drop by drop for an hourand then it was stirred at room temperature for three more hours. To thereaction mixture ethyl acetate (60 ml) and 0.1N hydrochloric acid (60ml) were added and the layers were separated. The ethyl acetate layerwas extracted with 5% sodium hydrogen carbonate solution (2×50 ml) andthe layers were separated. The aqueous layer was acidified with 0.1Nhydrochloric acid to pH 1, then fresh ethyl acetate (60 ml) and sodiumchloride were added and the layers were again separated. The ethylacetate layer was washed with brine, dried and evaporated to a dryresidue, which crystallized upon drying at 0.1 mm Hg (0.931 g; 77.0%).

m.p. 106°-110° C.

Rf=0.50 (ethyl acetate-methanol 3:1)

IR(KBr): 1800(vs), 1700(s), 1630(m), 1430(m), 1370(m), 1285(m), 1245(m)cm⁻¹.

¹ HNMR(CDCl₃)(300 MHz)δ: 2.065 (3H, s, Me), 2.33 (3H, s, Me) and 6.27(1H, s,C₂ --H) and 9.57 (1H, b, COOH) ppm.

I claim:
 1. 2-nitroxy derivatives of 3-bromo- and3,3-dibromo-4-oxo-azetidines of the formula I ##STR4## wherein R¹ ishydrogen or bromine,R² is hydrogen or bromine, wherein at least one ofR¹ or R² is bromine, R³ is hydrogen; Me₂ --C═C--COOR⁴ wherein R⁴ ishydrogen, methyl, benzyl or some other carboxy-protective group, and Xis nitroxy group (--ONO₂).
 2. The 2-nitroxy according to claim 1,characterized in that R¹ is hydrogen, R² is bromine, R³ is Me₂--C═COOR⁴, R⁴ is methyl, and X is nitroxy.
 3. The 2-nitroxy according toclaim 1, characterized in that R¹ is bromine, R² is hydrogen, R³ is Me₂--C═COOR⁴, R⁴ is methyl, and X is nitroxy.
 4. The 2-nitroxy according toclaim 1, characterized in that R¹ is bromine, R² is bromine, R³ is Me₂--C═COOR⁴, R⁴ is methyl, and X is nitroxy.
 5. The 2-nitroxy according toclaim 1, characterized in that R¹ is hydrogen, R² is bromine, R³ is Me₂--C═COOR⁴, R⁴ is benzyl, and X is nitroxy.
 6. The 2-nitroxy according toclaim 1, characterized in that R¹ is bromine, R² is hydrogen, R³ is Me₂--C═COOR⁴, R⁴ is benzyl, and X is nitroxy.
 7. The 2-nitroxy according toclaim 1, characterized in that R¹ is bromine, R² is bromine, R³ is Me₂--C═COOR⁴, R⁴ is benzyl, and X is nitroxy.
 8. The 2-nitroxy according toclaim 1, characterized in that R¹ is hydrogen, R² is bromine, R³ is Me₂--C═COOR⁴, R⁴ is hydrogen, and X is nitroxy.
 9. The 2-nitroxy accordingto claim 1, characterized in that R¹ is bromine, R² is hydrogen, R³ isMe₂ --C═COOR⁴, R⁴ is hydrogen, and X is nitroxy.
 10. The 2-nitroxyaccording to claim 1, characterized in that R¹ is bromine, R² isbromine, R³ is Me₂ --C═COOR⁴, R⁴ is hydrogen, and X is nitroxy.
 11. The2-nitroxy according to claim 1, characterized in that R¹ is hydrogen, R²is bromine, R³ is hydrogen, and X is nitroxy.
 12. The 2-nitroxyaccording to claim 1, characterized in that R¹ is bromine, R² ishydrogen, R³ is hydrogen, and X is nitroxy.
 13. The 2-nitroxy accordingto claim 1, characterized in that R¹ is bromine, R² is bromine, R³ ishydrogen, and X is nitroxy.